That´s great news, Bernt.
Did you get any indication if it is orderable and in what quantities?

Just a quick check: Have you considered the Phote resist method?
It would require a pattern on plastic but it can on the other hand be re-used.
Using a wide and shallow bowl, you don´t need the "Etsaggregat".

Yes i have thought at that.
But i have read about another way of doing that:http://www.diyaudio.com/forums/solid...-super-77.htmlPost 764.
Use a laserprinter to print the pattern and a laminating machine to transfer it to the alu/mylar.The machine has to be adjusted to a higer temperature.

Can you try the white benzene on your kapton and let me know how quickly the glue comes off vs the rubber adhesive on the polyester tape?

It took a couple of minutes to remove the adhesive from a 185 mm x 480 mm membrane. I tested some kapton, and it should take the same amount of time.
One problem is that you cannot easily see when the adhesive is removed on kapton.
With the 3M film it is much easier as the polyester is colorless and the adhesive yellow.

It took a couple of minutes to remove the adhesive from a 185 mm x 480 mm membrane. I tested some kapton, and it should take the same amount of time.

Thanks very much for checking this. I suppose that I'll have to get some of that solvent. This kind of kapton is of course a bit thick and so on, but it's still interesting (and cheap) to play with. I figure that I can use it to much some planar headphones drivers too - the diaphragm of the Fostex T50rp is rather heavy but still performs wonderfully.

I tried printing on Al as well - my laser printer did not leave a perfect trace pattern (had gaps) but that may have been from the foil not being flat enough.

I think I still will do some tests regarding etching of alu/mylar film.
I have not asked the supplier of alu/mylar about quantities yet.Wanted to test it first.
I need some high gloss thin photopaper (80 LB) What is this in gr/m2,or thickness ?I think 12 mill or 30my.
I am not trying to get the AMT to play lower than 1khz.
I am going to make planars to get lower.

I have been discussing AMTs as dipoles with StigErik, and he feels the TPL-150 is too tall to be a proper dipole and prefer the smaller Mundorf AMT. The Mundorf has issues with reflections against ceiling and floor because it spreads the sound more vertical. The TPL-150 is very limited vertically, which is a good thing in this case. He ended up with the 2 meter high Bohlender RD75, that solves this problem with reflections. Anyway, what is how I got it explained to me. The RD75 is difficult to get shipped here and is very expensive. How about a 2 meter high planar as a next project? Or maybe a shorter Mundorf version.

Built a 7' high by 2' wide planar speaker, using 50 x 12.7 x 3 mm neos which was full range and didn't need a tweeter! Using MDF for the frame, no need for a crossover. Using 3 mm alu tape, easy peasy.

I don't have any RD75's anyway. Goes down to 20 Hz. I think overall I prefer the ones with ferrites, the neo ones are a bit top heavy and are harder on the ears. I don't do any measurements as I don't have the equipment or the inclination. As I have 10 of my planars running in all channel stereo at the same time, it is difficult to measure! I am not really a technical person, I just like to build and listen. I never write enough down with all my rebuilds, I can't really be bothered at my time of life (75). I wish I was more organized, but one cannot help being what one is! At this time I am building planar headphones, which is quite fiddly especially the smaller ones. I am just waiting for my EUREKA moment, if it ever comes to get some new ideas so I can build some more speakers. Or I may just start building valve amps again, as I have a few in the pipeline!!??